Cloud Syncing - State of current tools?

Hi community,

I've had an app on the store for a few years now that relies on Core Data to store some relational data. (In this case it's semester and class information.)
I'd like to add multi-device syncing to my app, but with Core-Data+iCloud deprecated since 2016, I'm not sure what my options are. I was hoping for something new to be announced at WWDC '18, but it came and went.
Has anyone else solved this for themselves?


Few bad ideas I've had:

Migrate all data out of CoreData and into some JSON files on startup, and just use iCloud Document syncing to make it work.

Create my own middleware so I can sync core-data records over cloudkit.


I'm only one developer, so adding a feature that has potentially a ton of edge cases and losing user data makes me nervous. I was hoping there would be a better way to do this by now.